Welcome to the world of achievement craft. It like interviewing for a job, but they want you to have experience. You cant get experience until you get a job... very mean cycle . If you are geared, gemmed, chanted correctly I will have zero issue taking you in an alt/pug run. If/when you manage to get into a run and dont know a fight, you have to tell the RL before hand to explain the fight. Nothing will make me kick you quicker than no one saying anything about not knowing the fight then dying to fire. I wont tolerate it, and you will be gone.
I play on a few different servers and see multiple runs every day for people doing old content or pug FL runs. It will require some effort but you will get into a run. Just do what your supposed to, and youll stick around. As fickle as people are in this game, groups are always needing players.
I actually have to disagree with the A vs B team. My guild runs 2 10 man teams. Each group helps the other, and has lead progression at some point. At the start we formed a "super group" to down FL bosses early then spread officers to each team. Its not hard to find guilds with multiple competent 10 man teams. If one team is having an issue the other teams officers pop into vent to help out with a fight. We want both teams to succeed, not one team to loot the spoils, and the other team to bang their face in a wall.